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Teeth Origin of Primates Origin of Primates II

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					                                                                                                                                                    5/4/2011




                               Teeth                                          Tarsier            Indri                     Mangabey
                                                                           (insectivore)      (folivore)                   (frugivore)
• Teeth exceedingly useful
  for paleontologists
  because they:
   – Enable phylogenetic
     reconstruction
   – Reveal life history and
     development patterns
• In addition they tell a lot
  about diet:
   – Insectivore – relatively long        Teeth are a paleontologists
     sharp incisors and canines            dream – these are sample
   – Folivore – sharp premolars             mammalian fossil teeth
     and small incisors
   – Frugivore – large incisors
     and small molars




                                                                           Origin of Primates II
              Origin of Primates I                                                                                             Field of vision in
                                                                                                                               typical vertebrate

• Arboreal Hypothesis                                                   • Visual Predation
   – Primates emerged                                                     Hypothesis
     because of adaptation                                                – Primates emerged as
     to arboreal life                                                       adaptation for hunting
   – Importance of sight                                                    insects in bushy
     over smell                                                             undergrowth
   – Depth p
        p perception
                   p                                                      – Binocular vision a
     facilitates leaping                                                    predator adaptation
   – Grasping hands and                   Many believe the earliest       – Hands and feet for
     feet for moving                   primates were like tree shrews       grasping insects
     through branches
                                                                                                     Many predators have binocular vision




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                                                                      1.8 mya      Epochs of the Cenozoic Era
           Origin of Primates III
                                                                      136 mya


• Mixed Diet                                                          190 mya                12 kya


  Hypothesis                                                          225 mya


                                                                      280 mya
   – Modern prosimians
     rely less on sight than                                          345 mya


     later primates                                                   395 mya


   – Primates emerged                                                 430 mya
                                                                                             34 mya

     around same time as                                                   y
                                                                      500 mya

     angiosperms                  Angiosperms, the plants that        570 mya

   – Earliest primates may      produce flowers and fruits, arose
     have had mixed diet of     about the same time as primates.

     flowers, seeds, fruits,
                                                                      Earliest may have lived in Paleocene.
     and insects




           Paleocene Primates
• Earliest primates may
  date b k to th
  d t back t the
  Paleocene
   – Based on genetic and
     phylogenetic
     reconstructions of
     branching patterns
• Fossils from this time
  period rare and unclear
  whether actually             It is unclear whether fossil species
                                  like Plesiadapis are primates.
  primates




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                             Epochs of the Cenozoic Era
              1.8 mya




              136 mya
                                         12 kya
                   y
              190 mya

              225 mya


              280 mya


              345 mya


              395 mya


              430 mya
                                         34 mya

              500 mya


              570 mya




                    Eocene was Age of Prosimians.




                Eocene Primates                                                                       Omomyids
• First fossil forms clearly
  identified as primates in
                 p                                                              • Fossil prosimians from
  Eocene (54 to 38 mya)                                                           E        N th America,
                                                                                  Eocene North A      i
                                                                                  Europe, and Asia
• Age of Prosimians
                                                                                   – Grasping hands and feet
• 60 genera in two main                                                            – Large eyes
  families                                                                         – Early members of this
   – Omomyidae                                                                       family may be ancestral to
   – Adapidae                     Tropical climates were more widespread in                 p
                                                                                     anthropoids
• Lemur ancestors first            the Eocene, such as in this reconstruction      – Later members may be
                                       of a North American environment               ancestral to modern
  arrived in Madagascar                                                              tarsiers                     Reconstruction of an omomyid primate
  during Eocene                                                                    – Nocturnal
   – Island was closer to
     mainland Africa than today




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                             Adapids                                          Anthropoid Evolution in Eocene
  • Fossil prosimians                                                       • Anthropoid suborder
    from North America,                                                             during   l    t f
                                                                              arose d i early part of
                                                                              Eocene
    Europe, Asia, Africa
                                                                               – Diverged from Omomyid                       Prosimians
     – Suite of adaptations                                                      ancestor
                                                                                                                             Monkeys




                                                                                                                                          Anthropoid
       very much like                                                          – Trend from nocturnal to                     Apes
       modern-day lemurs                                                         diurnal led to increased
       and lorises                                                               importance on sight over
                                                                                                                             Humans




                                                                                                                                                   ds
                                                                                 smell
     – But, did not posses
       dental comb                                                          • Eosimias – China
                                                                                                                Anthropoids diverged from
                                                                            • Catopithecus – Egypt              prosimians in the late Eocene


                                     Smilodectes is a species of Adapid.




                                                                                                        Epochs of the Cenozoic Era
             Anthropoid Adaptations                                                       1.8 mya




                                                                                          136 mya
• Today, anthropoids                                                                                            12 kya

  include monkeys apes,
          monkeys, apes          Anthropoid                   Prosimian                        y
                                                                                          190 mya

                                                                                          225 mya
  and humans
                                                                                          280 mya
• Early anthropoids were
  monkey-like                                                                             345 mya


• Differed from                                                                           395 mya


  prosimians:                                                                             430 mya
                                                                                                                34 mya

       y
   – Eyes rotated more                                                                    500 mya
     forward
                                                                                          570 mya
   – Fully enclosed eye socket
   – Dry nose separate from
     upper lip
   – Molar cusps
   – Shorter “snout”
                                                                           Anthropoids were the most numerous primate during the Oligocene.




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         Oligocene Anthropoids                                              Anthropoids from Fayum
• During Oligocene,                                                 • Fayum
    th    id became
  anthropoids b                                                        – Today – desert
  most numerous primates                    Prosimians                 – 36-31mya – tropical forest




                                                      Anthropoids
  – 38 to 23 mya                            Monkeys                 • Anthropoids from Fayum,
  – Most knowledge of these                 Apes                      Egypt, lived in trees and
    primates from Fayum,                                              ate fruits and seeds
    Egypt                                   Humans                  • Parapithecid family
  – Other specimens found in
    North and West Africa,                                             – Small
                                 Anthropoids diverged from
    southern Arabia, China,     prosimians in the late Eocene          – Ancestral to NW monkeys        Parapithecids may be
    Southeast Asia, and North                                       • Propliopithecid family          ancestral to NW monkeys
    and South America                                                                                   like these capuchins
                                                                       – Ancestral to OW monkeys,
                                                                         apes, and humans




                                                                                    Aegyptopithecus
                                                                    • Propliopithecid from
                                                                      Fayum, Egypt
                                                                       – 13 to 18 lbs
                                                                       – Relatively small brain
                                                                       – Shares dental formula
                                                                         with later catarrhines
                                                                          • 2:1:2:3                         Anthropoids diverged from
                                                                                                            A th     id di       df
                                                                          • Just two premolars             prosimians in the late Eocene

                                                                       – May be ancestral to
                                                                         later catarrhines




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                                                                                                       Epochs of the Cenozoic Era
              New World Monkeys                                                         1.8 mya




                                                                                        136 mya
 • First species in South                                                                                      12 kya
                                                                                             y
                                                                                        190 mya
   America d i th
   A     i during the
                                                                                        225 mya
   Oligocene
                                                                                        280 mya
 • Unclear how they got                                                                 345 mya
   there
                                                                                        395 mya
     – Continents of Africa and
                                                                                        430 mya
       South America already                                                                                  34 mya
                                  The first platyrrhines are a mystery
       separated by 2000 miles                                                          500 mya

     – Descended from N.                                                                570 mya
       American primate?
     – Perhaps anthropoids
       emerged much earlier
       when continents were                                              Hominoids were the most common primate of the Miocene epoch.
       closer




               Miocene Hominoids                                                                  Proconsul
                                                                         • 4 early Miocene (23-
• Today, apes relatively rare
                                                                           16mya) ape species from
• In Miocene, around 100                                                   Africa
  species of apes lived
                                                                            – Perhaps descended from
   – Range from size of                                                       Oligocene propliopithecids
     house cat to size of                                                   – Ape-like teeth
     gorilla                                                                – Monkey-like postcrania
   – Diet varied more than                                                  – Size varied (some with
     diet of apes today                                                                            p
                                                                              marked sexual dimorphism)  )
                                                                            – Dentition suggests diet of                Proconsul
   – Locomotion more                Miocene was the Age of Apes
                                                                              fruit and leaves
     monkeylike                                                             – Replaced by OW monkeys
                                                                              and later apes species by
                                                                              middle Miocene (16-
                                                                              10mya)




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                    Afropithecus                                          Eurasian Apes
                                                      • Middle/late Miocene apes
• Afropithecus (18-16mya)                                    y p
                                                         – Dryopithecus
     Slow moving
   – S
                                                         – Sivapithecus
   – Ape front teeth and thick
     enamel on back teeth for                         • Large incisors, bladelike
     processing nuts or other                           canines, and long back
     hard foods                                         teeth
   – Ancestral to species that                        • Modern ape life histories
     crossed from Africa to
                                                        a d oco ot o
                                                        and locomotion
     E     i
     Eurasia
                                                         – Slow maturation            Sivapithecus
• Middle Miocene (16-
                                                         – Long lived
  10mya) saw spread of                Afropithecus
  apes throughout Eurasia




                    Dryopithecus                                          Sivapithecus
• Several species of Dryopithecus in Europe           • Sivapithecus is an Asian
                                 (10 5mya)
  during middle and late Miocene (10-5mya)                        i from th
                                                        ape species f     the
  – Y-5 pattern of molar                                middle and late Miocene
  – Some scientists view a species like this one to   • Thought to be ancestral
    be ancestral to modern African apes and             to modern orangutans
    humans                                            • When first found, some
                                                        anthropologists believed it
                                                                                          Sivapithecus
                                                        was possibly ancestral to
                                                        all apes and humans




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                                            Is it Possible to Find a Missing Link?
                 Gigantopithecus
• Largest primate ever
   – Gigantopithecus – Asian
     ape that lived from Late
     Miocene to very recently
     (300 kya)
   – Based on ratios of jaw and
     tooth size to body size in
     other apes, largest estimate
     is that Gigantopithecus
     stood over 10 feet tall and
     weighed 1,200 pounds
   – Must have been a ground-
     dwelling ape
   – Some wrongly suggest it is
     still alive as the yeti and
     Bigfoot




    Fossils Provide an Incomplete Picture   Fossils Provide an Incomplete Picture




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